top | item 5436614

Can We Stop Drawing Trees on Top of Skyscrapers?

245 points| tumblen | 13 years ago |archdaily.com | reply

132 comments

order
[+] AlexMuir|13 years ago|reply
We have an incredible 4000sq ft olive grove at the top of the 48 storey Beetham Tower in rainy Manchester. The architect turned the top two floors into his own penthouse, complete with enclosed olive trees.

Picture: http://www.bbc.co.uk/manchester/content/articles/2009/04/27/...

Trees at the top of a skyscraper convey both extravagance and eco credentials. Helipads are no longer credit-crunch-friendly.

Video (Skip to 1:16 for the trees)

http://karmacrew.tv/our-work/architect-profile-ian-simpson-b...

[+] ChuckMcM|13 years ago|reply
Well that certainly skewers the claim in the article that it will "never" happen :-). I note that these trees are effectively indoors as opposed to many of the architectural conceptions of being out doors (and the primary objection of the author).

That said my biologist friend says that trees are a lot hardier than the author gives them credit for, in particular many evergreens are adapted to living in pretty harsh climates and their needles are better able to deal with high winds and temperature extremes. His question was "where are the roots" since a 25' tall tree might have a 10' root 'ball' holding it in place. So if you don't mind having a floor of 'dirt' and then the tree on the next floor up, and you don't mind your tree being an evergreen, you can probably do something sustainable.

[+] GFischer|13 years ago|reply
There are several other buildings with trees inside, in Buenos Aires (Argentina), one of the tallest towers (the YPF tower, by architect César Pelli), has an Eucalyptus grove inside.

http://www.flickr.com/photos/guido-martinez/4686769123/

http://www.skyscrapercity.com/showthread.php?t=342972&pa...

In Mexico City, you have "La Torre del Árbol" (Tree Tower), with a baobab tree that goes outside a window on the 9th floor, it has now grown up to the 13th floor

http://www.judastechnologies.com/2009/10/30/la-historia-no-a...

Edit: j1o1h1n mentioned the Capita Centre in Sydney, Australia:

http://www.sydneyarchitecture.com/cbd/cbd4-008.htm

Le Corbusier built the Curutchet building in Buenos Aires, also with a tree in the middle:

http://majocobe.blogspot.com/2009/01/casa-del-doctor-curutch...

Edit: an amazing amount of examples from everywhere from Vancouver to Paris to New York to Chicago in the comments.

[+] graeme|13 years ago|reply
I am pleased that the architect lives in his own building. Inspires confidence in the buildings design.
[+] jellicle|13 years ago|reply
Toronto requires green roofs for new building projects. Grasses and shrubs are typically grown, and they survive just fine with minimal care. I suspect the only reason that large trees are not typically used is that there's fear that tree roots will damage the roof of the building. Oh, and the weight of the soil required for larger plants is an issue.

Yep, looking at the bylaw, the growing medium - soil - is only required to be four inches deep. Weight of soil and drainage starts to be a problem - you have to figure that the soil may be 100% soaked...

It's going to be tough to grow trees in four inches of soil.

So, nutshell, tree survivability not a problem, but engineering a roof to hold enough soil (and therefore water) to grow a large tree is expensive, and root damage is a problem, and therefore - no large trees on skyscrapers. Still, there's nothing magic about it, just engineering problems. I could easily imagine a high-end residential tower with a forest on the roof.

[+] willyt|13 years ago|reply
Just to add some more information to your comment, I'm an Architect and I worked on a building with trees growing on top of a structure, but not at high level. I just happen to know that, according to the tree specialist, a 5-8m tall magnolia tree can probably survive in a cube of soil 1.5m x 1.5m x 1.5m encased in a concrete pit lined with a geotextile to prevent root damage to the structure. It needs to be hooked up to a fairly sophisticated hydroponic system to keep it alive and their growth will be stunted by the restrictions placed on the root ball. Another issue with some of the trees shown is that, because they are under the structure, they will need to be turned every couple of years and/or illuminated with special lights to keep them from being distorted by growing towards the sun and to ensure they receive enough light to photosynthesise.

More generally, the computer renderings you see in the article are often generated by students or outside design agencies based on sketches and other early information from the architects. They are done in a few weeks often to very tight deadlines and are definitely not based on technical drawings so you can get all kinds of weird stuff in there depending on how imaginative the computer graphics person is and how late they had to stay up to beat the deadline. A real skyscraper takes years to design, the details of how tree pits work wont be fully bottomed out until a few years after the fancy renderings are done. Ultimately, trees often disappear from the finished product once it has permission from the city as the developer will be looking for ways to cut costs; things like this often get the chop unless there are specific conditions to keep them in the design that have been placed on the permission granted by the local authority.

[+] morsch|13 years ago|reply
Can you provide any reference/elaboration for your claim that tree survivability is not a problem? It's directly counter to the arguments made in the article. Grasses and shrubs are a lot more hardy than trees, as anybody who's even been on a mountain can attest to.

Your other points are well taken and they are sort of addressed in the article in the form of the infrastructure issues. I think the author also would agree that it's sort of feasible in theory, but extremely expensive and impractical.

[+] abduhl|13 years ago|reply
I would go out on a limb here and say that the weight of the soil and drainage issues are not relevant. We're talking 100 pcf or so for saturated organic soil and drainage is pretty easily taken care of with geotextiles. 300 psf isn't overly large for a dead load when you note that live loads should not be applied over the same area as it isn't a space that should have traffic during a significant load combination.

Your second point about root damage has more merit but still doesn't seem like a hard problem.

[+] Lewton|13 years ago|reply
You just gave MORE reasons why it can't happen, you never refuted any of the original claims by the article
[+] ryguytilidie|13 years ago|reply
San Francisco actually does the same. The roof of the building Haakasan is in is a great example. Pretty sure the twitter roof also has trees.
[+] lttlrck|13 years ago|reply
Grasses and shrubs != Trees
[+] Spooky23|13 years ago|reply
You can grow trees on skyscrapers. But the author captured why it is unlikely to happen: trees need care & maintenance. Care & maintenance == $.

For the types of people who build and run skyscrapers, facility operations is a cost center, and regulating authorities don't really care about greenscape. Nobody wants to pay for a staff of gardeners.

That's why when plans get mocked up, the public spaces around commercial buildings are usually lush, but when the building are actually constructed, you see a few shrubs or maybe a few arbor vitae at ground level.

When the local people and regulating bodies care, things are different. The Wal-Mart parking lot in Hilton Head Island, SC is wooded and shaded. The town refuses to issue construction permits that require old growth trees to be cut down -- so there's 60" wide tree in the lot, with a buffer between it and the pavement. Instead of curbs directing water to storm drains, there are mulched beds that absorb alot of storm water. About 15 miles away near I-95, there is another Wal-Mart with the typical construction methods -- bulldoze, flatten and pave everything.

[+] josefresco|13 years ago|reply
I feel like most of the replies are focusing on the feasibility of putting trees in or on skyscrapers when I think the criticism levied in the article was more towards "designers" or architects who are using them as decorations knowing they will never get to see actual production.

I don't think it actually matters to the author if trees can live and thrive in this environment but more so if they are actually implemented.

Including something in your design to make it special (or to win a project) knowing it will never be implemented is a design problem and one that could be translated to what we (hackers) do with technology projects.

[+] ryanklee|13 years ago|reply
I feel like

> There are plenty of scientific reasons why skyscrapers don’t—and probably won’t—have trees, at least not to the heights which many architects propose.

implies strongly and clearly enough that the author doesn't think it's feasible.

That said, he's also clearly annoyed that designers/architects are being unrealistic in their proposals.

[+] 7952|13 years ago|reply
There is a history of putting large plants inside glass buildings at ground level. Because in a building with amazing views and glass walls you should make people look at something that is trite and artificial! Skyscrapers are already in a sometimes beautiful dynamic natural environment (the sky). Putting trees in the sky is absurd.
[+] sk5t|13 years ago|reply
Two other things about trees:

* They hold tons and tons of water and are generally massive (if you've never given a hardwood tree a good pruning, the volume and mass are surprising). A large, growing tree and its root system would add very significant load to the structure.

* They blow over sometimes. Probably frequently, on an exposed, elevated rooftop with limited soil depth (shallow roots, fairly easy to saturate). 20 tons of tree flying off a tower during a storm doesn't sound like fun.

[+] up_and_up|13 years ago|reply
> Life sucks up there. For you, for me, for trees, and just about everything else except peregrine falcons. It’s hot, cold, windy, the rain lashes at you, and the snow and sleet pelt you at high velocity. Life for city trees is hard enough on the ground. I can’t imagine what it’s like at 500 feet, where nearly every climate variable is more extreme than at street level.

How is being located on top of a tall building much different from being located on top of a tall hill or mountain? Wouldn't the only factors involved be the type of soil and species chosen?

[+] jcmontalbano|13 years ago|reply
Oh man what an interesting question!

The short answer is that a tall hill or mountain represents a broad elevation change that's contiguous with the surrounding landscape. Difference in air quality from sea level is not a simple function of elevation, but of air flow and direction. You actually have to treat the air near the surface as a flow.

Check out this extremely kickass old film: http://youtu.be/7SkWxEUXIoM?t=29s The drag near the solid surface greatly slows down, and introduces turbulence to, an otherwise laminar flow. This means that the air near the surface of the earth is doing a lot more interacting with the earth than the other air, and is getting and keeping a lot more heat and dissolved gases. Above that turbulent layer, you just have cold dry air. It loses heat, water condenses, gases fall out.

What can you use as an indicator for the height of the wet air layer? The height of the local trees! Their tops are about at the top of the survivable boundary layer in the air. Desert plants are short, rainforest plants are tall. Interestingly, this might lead you to wonder where the tallest trees in the world are.

Probably in some place where there's an ocean wind that blows into a blind valley, right? Because that thick boundary layer would just pile up and up, right?

Here's an elevation map of California: http://www.netstate.com/states/geography/mapcom/images/ca_h....

And here's where the Giant Sequoia redwoods are: http://www.yosemite.ca.us/library/sequoias_of_yosemite/distr...

So being on top of a tall building is like being on a spike up above the livable atmosphere for trees. Unless your city is built in a place that already had giant trees, it won't have much success growing them at heights above their native height.

Unless you choose very specific trees.

[+] DanBC|13 years ago|reply
Attrition rate for saplings is pretty high. So in nature when you see a bunch of trees on a hill there are many more trees that didn't survive. But in a building you don't get to have any attrition; you want all trees to survive.

And city buildings can generate surprisingly strong winds. "The wind loading on a skyscraper is also considerable. In fact, the lateral wind load imposed on super-tall structures is generally the governing factor in the structural design. Wind pressure increases with height, so for very tall buildings, the loads associated with wind are larger than dead or live loads."

(https://en.wikipedia.org/wiki/Tall_buildings#Design_and_cons...)

[+] alberich|13 years ago|reply
I guess he addressed this point. There are plants well adapted to life on top of a tall mountain... though it's not the beautiful tall trees depicted on the mockups. I'm guessing those plants probably are short shrubs with dark green leafs and contorted trunks.
[+] rhplus|13 years ago|reply
My guess is that the raw exposure is a big deal. Trees on hillsides or mountainsides only have one side fully exposed, so there's a dominant direction they could brace against. They would also benefit from having other trees (and a mountain) next to them to help dissipate the energy from the wind and rain.
[+] DanBC|13 years ago|reply
I think this shows the problem that people like me have with design.

I don't notice good design. Things just work and everything is where it should be. It's taken hundreds of years of collected wisdom and research and skill to get it like that, and someone has worked very hard to make it so I don't notice their work.

I do notice when someone draws a willowy slender tree on the side of a towerblock. It'd be great to have more shrubbery and trees up high, but at least they could do it realistically. And I get the impression that they forget about all the root system and maintenance and etc.

England has a problem with terribly dull architecture.

[+] ThomPete|13 years ago|reply
This is not about good design, this is about whether it's possible.

If it was possible it would certainly not be a bad idea as it would allow for even more interesting types of architecture.

So you might not notice it, but you do reap the benefits of good design (which should not be confused with aesthetics)

[+] ry0ohki|13 years ago|reply
Maybe there is a certain height where this comes into play, but I've seen trees growing naturally (not by design) in abandoned buildings. The first I could think of is the 13-story Highland building here in Pittsburgh you can kind of make out the quite large tree in this photo http://photos.mycapture.com/PITT/1314621/37517652E.jpg
[+] cperciva|13 years ago|reply
There's another reason to not have trees on top of skyscrapers: It's dangerous.

Even the best-pruned tree will occasionally have the occasional branch break off in a severe storm. Normally that's not a problem -- but if the tree is 300' in the air, that branch can go flying a long way and hit someone with a lot of force when it reaches ground level. The sorts of companies which build big skyscrapers don't like to take risks like that; nor do most city zoning boards.

[+] maratd|13 years ago|reply
> Even the best-pruned tree will occasionally have the occasional branch break off in a severe storm.

I would imagine it's not that easy for a tree to truly root itself in whatever shallow sandbox they plant it in. You're more likely to have the entire tree fly straight at you.

[+] wyck|13 years ago|reply
Mister Spock has a 30 foot tall oak tree on top of a building for many years now, http://farm4.staticflickr.com/3228/2896752060_d5bd34df28_z.j...
[+] RutZap|13 years ago|reply
That's nice but that is hardly a skyscraper. By the look of it the building is around 15 floors high... let's say around 40m high. The author was talking about putting trees at 500feet in the air, that's 152m... considerably more.
[+] bargl|13 years ago|reply
I get what he's saying. I think he's more upset that architects are using a "tree" to add some level of trendiness to their buildings. When in fact they should be adding altitude hardened plants that are typically not the most aesthetic plant.

But it is after all just a model and hopefully someone will sit down and scratch their head and say, wait what happens if a branch falls off that tree? Lets just put some bushes up there that don't grow past the railing...

[+] raverbashing|13 years ago|reply
Funny

"Trees won't survive in this conditions", but in Nature they are not watered, they are not pruned, and they have lived for millions of years

What harsh conditions are there in the side of a building that don't exist in nature? (Off the top of my head there are several, but it would be nice for him to specify)

It could be: temperature, winds, lack of cover (either soil cover or taller trees) and their corresponding soil dynamic.

But it shouldn't be too complicated to find a plant that works there.

[+] smurph|13 years ago|reply
I'm a bit surprised that the article never mentioned the potential affects of the tree's roots on the structures supporting them. My driveway can tell you that the roots of a decent sized tree will not play nice with man made things that get in their way.
[+] nonamegiven|13 years ago|reply
Yeah, I wouldn't want my unit under or around whatever space was reserved for the roots. Nor would I want my unit next to or under any of those units. After enough years a root will break through just about anything, or at least stress it. Then comes the water. And the critters.
[+] Glyptodon|13 years ago|reply
I think the writer is being a bit unrealistic.

So long as you aren't somewhere at a rather high elevation to begin with, the temperature, elevation and wind chill factors seem like they'd be quite easy to work around. Even something as simple as buffering vegetation from the prevailing wind direction ought to go a long way.

Perhaps a more relevant point might be that the architects aren't fully designing their vegetation's support systems, but that seems like it would require a higher burden of proof. I wouldn't be surprised if issues such as 'what if a large branch fell off 500 feet above street level?' aren't fully thought out, either.

But I don't think there's any reason that someone using careful engineering and design couldn't put healthy plants on a tall building.

If he was merely intending to point out that many architects are placing vegetation without proper design and engineering, he may be right, but I don't think he really succeeded in making the point.

[+] ichtet31|13 years ago|reply
I live @ 9200 ft in the rocky mountains in colorado. Plenty of tree growing right out of the granite. It amazes me how easily plants and trees can make their homes here. At these altitudes, a wide, horizontal root system works better than a deep vertical root system. It is definately within our ability to plant trees on top of buildings.
[+] blocktuw|13 years ago|reply
I'm wondering if the author has ever seen a tree on the side of a mountain or cliff - it's hard to stop a tree from growing if they are left alone. He makes trees sound like whiny children who require constant pampering. Not the things that have been on earth longer than any invertebrates and will most likely out survive our species.
[+] alan|13 years ago|reply
Looking at those pictures, I wonder "Where are the roots?" It's like the artists think the tree stops where the trunk meets the surface. I see rooms where peoples would be walking just under the trunk of the tree.

I could see using Bonsai style root trimming and enclosed spaces for the trees, but yeah, other than that it looks like pure fantasy.

[+] kalms|13 years ago|reply
Please make it viable instead of halting it, just because it's hard.
[+] SeanLuke|13 years ago|reply
Apparently someone hasn't heard of the Guinigi Tower.

Trees on top of buildings didn't used to signify green. They used to signify power.

[+] mapleoin|13 years ago|reply
Guinigi Tower's height doesn't come close to that of a modern skyscraper.
[+] Nux|13 years ago|reply
Please do not stop!

I absolutely love the idea of buildings lush with vegetation, as if in some post-apocalyptical world where nature has reclaimed the cities.

It may not be very possible/feasible, it may even be a public safety hazard, but I'm so fed up with steel, concrete and glass.

[+] pauljz|13 years ago|reply
Agreed. I think a blanket "Don't even try" is silly, and antithetical to the ethos of HN. I'm surprised there isn't more backlash against this.

"Don't just draw them on the skyscraper, make it work." would be a better sentiment. If wind is a problem, find a way to break the wind. If roots are a problem, find a way to stop the roots, or trim the roots, and build that into the design.

But there's a pile of evidence for the benefits of adding greenery to cities, so please just don't say to stop trying.

[+] ams6110|13 years ago|reply
Some form of vegetation may be feasible. I think the author makes a fairly good argument that trees are not it.
[+] jahewson|13 years ago|reply
> post-apocalyptical world where nature has reclaimed the cities

We are natural.